of chicago



y A. R. SCHWARZKOPF ,8 6,713

HYDRAULIC RAISING AND LOWERING MECHANISM FOR IHAIR SEATS Filed Oct. 1,1928 JiUTPJZZOZ J Patented May 26, 1931 UNITED STATES PATENT OFFICE IARTHUR R..SGHWARZKOPF, OF OHI CAGO ILLINOIS ASSIGNOR TO THEO. A. KOCHSCOM- PANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS HYDRAuLIoRAISING ANnLowERIuG MECHANISM non oHAIRsEATs Application filed October1, 1928. Serial No. 309,417.

This invention relates to hydraulic raising and lowerlng mechamsm forchalr seats, and

has reference more particularly to that type V of chairs known asbarbers chairs and dentists chairs, although the particular constructionherein described is capable of use 1n other situations where it isdesired to raise and lowera seat or other support. I p The principalobject of this invention is to provide novel means in the pump bucket ofthe'dev-ice for cushioning the same when the hand lever is moved intothe extreme down postion for lowering the chair seat; Another object isto provide a novel pump bucket having a check valve adapted to unseatthe valve which controls the passage of liquid from the main supportingcylinder to the seat supporting stem when lowering the latter. Another"object is to provide cushioned stops :0 for absorbing the jar usuallyoccasioned when the pump bucket is moved to the lower limit thisinvention consists in the several novel features of constructlon,arrangement and combination of parts hereinafter fully set forth andclaimed.

The invention is clearly illustrated in the drawings accompanying thisspecification in which I Figure 1 is a central vertical longitudinalsection taken through hydraulic raising'andl lowering means for chairseatsembodylng a simple form of the present invention;

Fig. 2is a vertical cross section taken on the line 22 of Fig. 1, butshowing the stem raised above the-position illustrated in Fig. 1; and

Fig. 3 is a fragmental vertical longitudinal'section showing the partsin the position occupied in Fig. 2, the plane of the section beingtransverse thereto.

Referring to said drawings, which illustrate one embodiment of thepresent invention, the. reference character 5 designatesa cylinder whichis supported and contained in the base of a chair (not shown) in thecustomary manner. It is here shown as provided with a flange 6 wherebyit may be attached to the base. The cylinder is open at its upper endand is closed at its lower end by an end wall 7 in which is a drainopening closed by a plug 8 threadedly secured therein.

Rotatably and slidably mounted in the cylinder 5 is a hollow cylindricalseat suporting stem 9, formed at its upper end with an enlarged orswelled-portion 10, at the upper edge of which is a flange 11 to whichthe chair seat (not shown) is bolted or otherwise secured. An annularshoulder 12 isformed between the stem 9 and enlarged portion 10, whichshoulder may seat upon the upper end of the cylinder 5 whenever the stemis lowered to the lower limit of its movement.

j The lower end of the stem 9 is closed by a head '13 in which is adischarge port. 14: through which liquid may pass from the in terior ofthe stem 9 to the interior of the cylinder 5 below the head 13. The port14 is controlled by a valve 15, here shown in the form of a taperedcheck valve, arranged to seat upon the tapered seat of the port 14. Thevalve 1'5 is held upon its seat by a spring confined between the valveand a bridge 16 secured to the underside of the head 13 by screws or thelike. The valve 15 is provided with a valve stem 17, oneend ofwhich is.

guided in'the bridge 16 and the other end of which projects above thevalve and above the upper face 18 of the head 13, and preferably is inthe form of a winged stem 19, whereby it is guided by the vertical wallof theportl l. i

Within the cylindrical stem 9 is the pump bucket 20 which is fittedclose to the machined portion 9 of the internalwall of the stem9 andreciprocates in the hollow of the stem. Below the machined portion 9?,the internal bore of the cylinder is slightly greater than that of themachined part 9?. A hand lever 21 is provided for reciprocating the pumpbucket, and in accordance with the usual.

practice, said hand lever has a sleeve 22 thereon which is rotatablymounted in the en larged portion 10 of the stem 9 and formed with acrank arm 23 connected to the pump rod 24 by a wrist pin 25. The lowerend of the pump rod is connected to the pump bucket by a pin 26 passingthrough upstanding ears 27 on the pump bucket and through the lower endof the pump rod. The upper end of the pump rod is preferably formed witha laterally bent or U-portion to enable the hand lever to be swung backfar enough to carry the wrist pin 25 beyond a vertical line passingthrough the axis ofthe sleeve 22. The usual brake shoe 28 may beprovided as is customary.

The pump bucket may be made hollow to provide a chamber, as is seen inFig. 2, and in its lower wall 29 is a port 30 normally closed by a valve31, preferably in the form of a tapered check valve seating upon atapered seat around the port 30. The stem 32 of the valve extends upthrough a bridge portion 33 which extends transversely through thehollow of the pump bucket, and above said bridge is a coiled compressionspring 34 which engages with a sleeve or other shoulder 35 upon thevalve stem 32 and acts to yieldingly hold said valve 31 upon its seat,thereby normally closing the port through the pump bucket.

The chamber of the pump bucket opens upwardly into the interior of thecylindrical stem 9 through an opening located between the ears 2'? and,as a preference, a screen or other strainer 36 is provided above saidopening to prevent any foreign matter from entering the chamber of thepump bucket. As shown, the screen or strainer 36 is secured to the upperface of the pump bucket by cap screws 37 threadedly secured indiametricaL ly opposed sockets 38 cast in the wall of the pump bucket.

Cushioning means are provided for absorbing any jar that may beoccasioned when the pump bucket is moved to the lower limit of its downstroke, and, as shown, said cushioning means comprise coiled compressionsprings 39, one contained in each socket 38 and confined undercompression between the lower ends of the cap screws 37 and short stemsor pins 40, which protrude from the bottoms of the sockets and areadapted to engage with the upper face 18 of the head 13 of thecylindrical stem whenever the pump bucket is moved to the lower limit ofits down stroke. The upper ends of the stems or pins 40 are formed withenlargements or heads against which the coiled compression springs bear.The heads of the stems 40 are adapted to rest upon the bottoms of thesockets to prevent the stems from falling through the sockets.

In the outer face of the pump bucket is formed a circumferential groove41 and leading from said groove into the interior of the pump bucket areports 42 which form bypasses through which liquid may pass from thelower side of the pump bucket into the interior thereof whenever thecircumferential groove 41 is brought down below the machined portion 9of the cylindrical internal wall of the stem. The ports 42 are ratherrestricted in diameter whereby the How of liquid therethrough isretarded in order that the cylindrical stem and the chair seat, which ismounted thereon, may move slowly downward when the liquid flows throughthe bypasses.

A body of liquid, usually an oil, is contained in the device and servesas a medium for raising and lowering the cylindrical stem 9 as well assupporting it in any adjusted position. The liquid contained in thatportion of the cylinder 5 below the cylindrical stem 9 serves to supportthe stem and parts carried thereby, and the liquid contained within thecylindrical stem may be forced into that portion of the cylinder belowthe stem to raise the latter.

In the operation of the device, and assuming the parts to be in theposition seen in Fig. 1, with the shoulder 12 of the stem 9 resting uponthe upper end of the cylinder 5, to raise the stem and parts carriedthereby, the hand lever 21 is oscillated back and forth with shortstrokes thereby reciprocating the pump bucket, and as the pump bucketmoves downward it forces the liquid contained between the pump bucketand head 13 of the stem past the check valve 15 into that part of thecylinder 5 below the head, thereby forcing the stem upward. As the pumpbucket moves upward the liquid contained in the stem above the pumpbucket flows past the check valve 31 into the enlarging space betweenthe pump bucket and head 13, and is thereafter discharged through theport 14 into the space below the stem 9 on the succeeding down stroke ofthe pump bucket.

Ill?) To lower the stem 9, the hand lever 21 is swung down in thedirection of the arrow thereon in Fig. 1 to the full limit of itsstroke, thereby bringing the lower face of the check valve 31 intoengagement with the winged stem 19 of the check valve 15 and unseatingsaid check valve 16, thereby permitting the liquid contained in thatpart of the cylinder 5 below the stem 9 to return through the port 14into the space between the pump bucket and head 13 of the stem, fromwhich it passes through the ports or by-passes 42 and through thechamber of the pump bucket, finally discharging out through the openingin the top wall thereof and into the upper portion of the stem.

It will be observed that in order to bring the check valve 31 intoeffective engagement with the stem of the valve 15, sufficient forcemust be applied to the hand lever to compress the springs 39 when thepins 40 impinge upon the upper face of the head 13. Said compressionsprings, therefore, not only cushion the shock which would otherwise becaused by the check valve 31 impinging upon the valve stem 19, but alsoserves as a cushion stop for the hand lever.

I claim:

1. In hydraulic raising and lowering mechanism, the combination of acylinder closed at its lower end, a cylindrical stem therein closed atits lower end and formed with a valve controlled port in said lower end,a reciprocatory valved pump bucket in said cylindrical stem havingcushioned limiting means disposed laterally of the valve of the pumpbucket and adapted to impinge against the head of the stem during thefinal portion of the down stroke of the pump bucket to retard movementof said bucket toward said head and valve controlled port, and means forreciprocating the pump bucket.

2. In hydraulic raising and lowering mechanism, the combination of acylinder closed at its lower end, a cylindrical stem therein having ahead at its lower end formed with a valve controlled port, a valved pumpbucket in said stem, spring pressed members disposed laterally of thevalve of the pump bucket and protruding from the lower face of saidbucket and adapted to impinge against the head of the stem to retardmovement of said bucket toward said head and valve controlled port whenthe pump bucket is moved beyond the lower limit of its pump ing stroke,and means for reciprocatingthe pump bucket.

3. In hydraulic raising and lowering mechanism, the combination of acylinder" closed at its lower end, a cylindrical stem therein having ahead at its lower end formed with a valve controlled port, a pump buckethaving a port therein closed by a downwardly opening check valve, saidcheck valve being arranged to impinge against and thereby unseat thefirst mentioned check valve whenever the pump bucket is moved to thelower limit of its down stroke, said pump bucket having also a normallyclosed bypass therethrough, cushioned limiting means arranged to retardmovement of the bucket during the final portion of its down stroke andto absorb shock on the pump bucket whenever the latter is moved to thelower limit of its down stroke in unseating the check valve of the portin the stem, and means for reciprocating the pump bucket.

4:. In hydraulic raising and lowering mechanism, the combination of ahydraulic cylinder closed at its lower end, a cylindribucket having alsoa normally closed by-pass therethrough, spring actuated cushion stopmembers protruding from said pump bucket and arranged to impinge againstthe head of the stem during the final portion of the down stroke of thebucket to retard movement thereof, and means for reciprocating said pumpbucket.

5.- In hydraulic raising and lowering mechanism, a chambered pump buckethaving a centrally located port leading from the chamber and a normallyclosed by-pass leading through the cylindrical wall of the pump bucketto the chamber thereof, a check valve for closing said port, a pluralityof sockets formed in the wall of the bucket, at places disposedlaterally of the port and check valve headed pins contained in andprotrudingfrom said sockets, and coiled compression springs in saidsockets and adapted to bear against said pins. V

6. In hydraulic raising and lowering mechanism, a chambered pump buckethaving an opening leading upwardly from the chamber,- and a valvecontrolled port leading downwardly from said chamber, a screen over saidupper opening of the chamber, sockets formed in the wall of the bucketfor receiving cushioning members, and means securing said screen to thepump bucket'and extending into a said sockets and forming abutments forsaid cushioning members.

In testimony whereof, I have hereunto set my hand this 28th day of Setember, 1928.

ARTHUR It. SCI-1W RZKOPF.

cal stem therein having a head at its lower 1 end formed with a checkvalve controlled port, a pump bucket in said stem and having a porttherethrough closed by a downwardly opening check valve, the latterbeing arranged to unseat the first mentioned check valve whenever thepump bucket is moved to the lower limit of its down stroke, said pump

